The Fat Inch

The Fat Inch is a tool that we’ve used for several years. It is a way to visualize fractions as units on a number line. The best method of constructing The Fat Inch is to use colored sentence strips all of equal size & length or you can take a group of paper strips and cut them into 12 inch segments. Each student will need five strips to construct his/her Fat Inch. The first strip represents the whole. Fold the 2nd strip once to represent halves. Fold the 3rd strip twice to represent fourths. Fold the 4th strip three times to represent eighths. Fold the 5th and final strip four times to represent sixteenths.

In Math Journeys 2012, Anna Friemel created a levelized problem Fat Inch lesson that has revolutionized the way we will teach the Fat Inch in the future. She basically created a leveled problem with the Fat Inch so that she could see what misconceptions her students have about fractions. Every fraction misconception you can think of was brought out in this lesson. Over the course of three days, she used the Fat Inch as a teaching tool to help build a strong fractional understanding. Watch the videos below to see how she implemented this lesson.

After students construct The Fat Inch, find a place in your room to place them so that they form a giant number line. Make reference to this tool when fractions are studied. For example, students can count by each unit fraction (1/2, 2/2, 3/2, 4/2, etc…) and compare that to a different unit fraction. Whenever comparisons need to be made this tool is a wonderful resource for students to use.

Check out the image below to see a small sample of what The Fat Inch looks like!

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1 Comment


    1. MJ 2011 Curriculum Order « Math Journeys

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